Chemistry

Chapter 3 and 4 Review Problems

a journey into the inner workings of matter!

Judith S. de Nuño

jdenuno@mhs-la.org

WebSites

http://members.home.net/jdenuno

Science at Marymount

Daily at Lunch in the

Science Patio

Cyber Office Hours

AIM: teachsci23

Significant Figure Rules

Metric Units

Give the Number of Significant Figures

• 1505 kg
• 3.85 x 10^-4 cm
• 17.2000 cm
• 13,000 m
• 13,000 km
• 13.000 mm
• 13,000.00 ml
• 9 baseballs
• 9 baseball players

• 17,000
• 237.85
• 0.00045
• 0.001003
• 0.005
• 1,000,000,000
• 4,000,000
• 0.00000004
• 850,000

• 384 g to kg
• 135 mg to ug
• 5 x 10³ km to m
• 25 cm³ to m³
• 25,000 mm to km
• 1.15 L to mL
• 85 mi/hr to m/s
• 75 g/mL to kg/cm³
• 24 hr to s

• 75 m to km
• 75 m/s to km/hr
• 75 m/s to km/day
• 75 m/s to km/wk
• 75 m/s to km/yr
• 25 m to nm
• 25 m to um
• 25 m to mm
• 25 m to cm
• 25 m to km

Solve the following problems. Rememember units, significant figures, and scientific notation!

1. Addition and subtraction (precise to term with least number of decimal places):

• a. 3.414 s + 10.02 s + 58.325 s + 0.00098 s = ____________
• b. 1884 kg + 0.94 kg + 1.0 kg + 9.778 kg = ____________
• c. 44.1 kg + 8.002 kg + 0.93 kg = ____________
• d. 2145.10 m - 465.109 m = ____________
• e. 2.326 h - 0.10408 h = ____________

2. Multiplication and division (precise to term with least number of sig figs):

• a. 21.3 cm x 9.80 cm = ____________cm²
• b. 10.19 m x 0.013 m = ____________
• c. 140.01 cm x 26.042 cm x 0.0159 cm ____________
• d. 80.23 m/2.4 s = ____________m/s
• e. 4.301 kg/1.9 mL = ____________

3. Solve the following prolbems:

• A car travels around a track 3 times. Your measurements for the 3 trials are 45.0 km/h, 48.21 km/h, and 57.024 km/h. Determine the average speed of the car. Use the addition subtraction rule for sig figs.
• An experiment calls for 16.356 g of substance A, 38.2 g of substance B, 0.0098 g of substance C, and 10.44 g of substance D. What is the total mass of the substances in the experiment?
• Calculate the volume in cubic centimeters (cm3) of a rectangular object that is 2.07 m long, 0.2533 m wide, and 0.695 m high. (V = l x w x h).
• What is the volume in cm³ of a rectangular object that is 685mm long, 63.5 mm wide, and 207.2 mm high?
• Calculate the length in cm of an object that is 10.8835 x 10⁵ mm long.
• A liquid has a density of 0.89 g/cm³. Express the density in g/mL
• A very small object is found to have a length of 5.44 x 10^-4 m. Express this length in microns.
• A sleeping bag for use in very cold climates is filled with 5lb of goose down. How may grams of down are used?
• This sheet of paper is 8 in x 11.5 in. What is its area in in² and in m³?
• The maximum freeway speed is 55 mi/h. What is this speed in km/h?
• If Janet got a ticket for going at a speed 20 mi/h faster than the freeway speed limit, what was her speed in km/h?

4. Determine the

• the number of kilometers in 205 meters
• number of meters in 6.0043 x 10^-3 kilometers
• number of microns (micrometers) in 0.86 meters
• number of cm³ in 75 mL
• number of m³ (cubic meters) in 5312 cm³
• number of dm³ in 1.733 x 105 m³
• number of mm in 5.27 x 10^-4 m

5. Convert

• 34,500 um to cm
• 22 cm to um (microns)
• 45 dm to mm
• 28,000 m to km
• 28,000 cm to km
• 28,000 cm to um

Denisty Problems

• How many grams are in 63.2 liters of alcohol, whose density is 0.79 g/mL ?
• A cube of gold that is 2.000 cm on a side has a mass of 154.4 What is the density of gold in g/mL ?
• A piece of silver (density = 10.5 g/mL) dropped into water displaces 21.56 mL of water. What is the mass in grams of this piece of silver
• Calculate the density of a liquid, 17.45 mL of which weighs 16.3 grams.
• Concentrated sulfuric acid has a density of 1.84 g/mL. Calculate the mass in grams of 1 Liter of this acid.
• What is the volume of pure sulfur (density = 2.07 g/mL) weighing 130 grams ?
• The density of glycerine is 1.26 g/mL . Calculate the mass in grams of 470 mL of glycerine.

Graphing Practice

• Organize the following information on density in a data table (TITLE THE TABLE).
  • Isopropyl alcohol:
    • 5 mL has a mass of 4.2 g
    • 25 mL has a mass of 19.9 g
    • 15 mL has a mass of 12.0 g
  • Water:
    • 15 mL has a mass of 14.8 g
    • 5 mL has a mass of 5.2 g
    • 25 mL has a mass of 25.2 g
  • Cooking Oil:
    • 25 mL has a mass of 23.0 g
    • 5 mL has a mass of 4.5 g
    • 15 mL has a mass of 13.6 g
• Construct a line graph (line-of-best-fit) for the data.
  • Use 3 different colors to represent the different substances.
  • Be sure to make a key, label the axes, and TITLE THE GRAPH.
• Determine the slope of each line from the graph or using the slope equation (change in y divided by change in x).
  • This value represents the slope.
  • The units are g/mL.
• Answer the following questions:
  • How can you determine which substance has the greatest density directly from the graph?
  • Which substance has the steepest slope?
  • Which substance has the greatest density?
  • Which substance has the smallest density?
  • How will the substances be distributed if poured carefully into a graduated cylinder. (which will be on the bottom, which in the middle, and which on top?). You can draw a diagram to illustrate your answer!